Kant on Essence and Nature Abstract: This paper investigates Kant’s account of “real essence” and of a thing’s “nature”. Notwithstanding their wide negligence in the literature, these concepts belong to the central ones of Kant’s metaphysics. I argue that, on the one hand, Kant is in continuity with the Aristotelian-Scholastic tradition of essence. But, on the other hand, he also follows Locke in distinguishing between “logical” and “real” essence. Contrary to recent attempts of aligning real essence with contemporary approaches to essence, I will defend the thesis that Kant equates real essence and (formal) nature, and that real essence has a causal, but no constitutive role. I shall also respond to potential objections and discuss some developments of Kant’s views. For a long time, the notions of “essence” and (formal) “nature” have been largely neglected in Kant scholarship, even though they belong to the key concepts of his metaphysics. The negligence of these concepts, however, is at least in part due to the fact that there is virtually no discussion of it in the published writings; thus it is easy to overlook their significance. For this reason, we have to rely mainly on the remarks in Kant’s Reflexionen and the transcripts of his lectures. There we find Kant situated between two traditions: on the one hand, he distinguishes, similar to Locke, between “logical” and “real” essence: whereas logical essence is the essence of concepts, real essence is the essence of things. On the other hand, Kant follows Wolff in the distinction of “essence” and “nature”: essence is the “principle of being”, nature the “principle of becoming”. According to a recent interpretative trend, this amounts to a tripartite division of 1. logical essence, 2. real essence, and 3. nature.1 This interpretation considers real essence akin to contemporary accounts of essence, according to which an essence constitutes what a thing is. Nature, by contrast, is taken to be the first causal ground causal ground or principle of a thing. In this paper, I take issue with this view. On the reading that I shall defend, the division is only twofold, namely between logical and real essence, where the latter is identical to nature. Put briefly, Kant combines Wolff’s account of nature and Locke’s account of real essence in a subtle and highly original way. Let me articulate my view in more detail. Setting nature aside for a second, there has been increased interest in essences in contemporary metaphysics2, and so it is no wonder that there is sort of a re- discovery of essences in Kant going on. Robert Hanna (2006: 166) conceives of real essence (on the microphysical level) as “a set of unobservable intrinsic non-relational dispositional properties”. Sebastian Rand (2012: 116) thinks that “the real essence of an object is the property or set of 1 See Stang 2016: 234, 239, Massimi 2017: 156f., Messina 2017a: 143f. Rand, on the contrary, appears to equate real essence and nature (see Rand 2012: 131 n. 24). 2 See, e.g., Fine 1994a, Zalta 2006, Lowe 2008. 1 properties of that object picked out by those concepts truly predicated of it in synthetic a priori propositions”. Nick Stang, finally, has recently provided a fascinating analysis of essence and nature and their connections to laws and modality. His view on real essence is as follows: [W]here K is a kind […] and x is a possible instance of that kind, the real essence of K is the complex of properties possessed by x that ground x’s being an instance of kind K. (Stang 2016: 236) I lack the space to discuss any of these views in detail. But what these authors have in common is that they think that essence consists of essential properties that make an object the thing it is. This is both a fairly traditional and a contemporary understanding of essence. But in the Scholastic tradition it was coupled to another aspect of essence, namely essence as the first ground, or even cause, of its properties. I shall call the former the constitutive role and the latter the causal role of essence.3 Kit Fine, a contemporary essentialist, claims that the causal role “is denied to any right-minded modern” (Fine 1994b: 19). Nevertheless, I contend in this paper that Kant, even though he may have room to accommodate the constitutive role within his system, only associates the causal role with real essence. Our discussion of real essence should center around four questions4: 1) What is the bearer of real essence? 2) What are the constituents of real essence? 3) What is dependent on real essences? 4) What is the grounding relation between real essence and the dependent entities? The best way to outline my interpretation of Kant, however, is by considering a further question: 5) Is real essence identical to the nature of a thing? When early modern philosophers before Wolff speak of the “nature” of a thing, as opposed to nature as the sum of material substances, then they mean roughly the same as “essence”, although it seems to have stronger connotations to causality. Wolff, however, draws a sharp distinction between “essence” and “nature”, where the latter consists of the causal powers of a thing. Kant, on the contrary, inspired by Locke, distinguishes between logical and real essence and equates real essence to nature. So I think that real essence, qua being identical to formal nature, consists of powers and can be a real ground only through them. For this reason, all things that are not substances – including 3 There is also the modal role of essence, which I briefly discuss in sec. 2.4. 4 These are the most relevant questions for my purposes at least. There may also be other important questions, e.g., whether essence is alterable, or how much we can know about it. 2 space, time, and mathematical objects – have neither a real essence nor a nature. My answer to the first four questions is thus, 1) real essence belongs to substances, 2) it consists of powers, 3) the grounded entities are accidents of substances, and, 4) the grounding relation is causal. As a result, the conception of real essence given here fundamentally disagrees with the views of those who think that real essence is different from nature: on my reading, real essence does not have a constitutive, but only a causal role. This does not mean that Kant cannot accommodate the constitutive role within his system – in fact, as I argue in section 3.4, real definitions seem to take over this task. Nonetheless, this paper should put pressure on interpretations that attempt to closely align Kant’s views on essence, grounds, etc., to contemporary debates. At the same time, it may also serve as a useful reminder to think anew about the causal role of essences – given the recent revival of powers5 and potentialities6, it might not deserve the short shrift that Kit Fine gives to it. The paper will begin with a brief overview of the tradition of essence and nature, focusing on Locke and Wolff, who had shaped Kant’s views on essence and nature most. The second section outlines the distinctions of logical and real essence and of formal and material nature, elucidates some other key metaphysical concepts, and then shows why real essence must be identical to formal nature. In the third section, lastly, I shall respond to a variety of possible objections, which will force me to acknowledge that some aspects of Kant’s account have changed over time. 1. The Historical Background According to the Aristotelian-Scholastic tradition of metaphysics, the essence of a thing determines what the thing is.7 It consists of an “entelechy”, or “substantial form”, which makes it belong to a species. But essence is more than that – it is also the ground and organizational principle of all or at least many properties of a thing.8 A classic example is that of an oak tree: while the tree is subject to changes over time, its substantial form determines its development, the forms of the leaves, etc. This picture is commonly associated with final causes and teleology, which makes it unattractive for many philosophers. But note that those are not the only causes that have their ground in an essence. Amongst others, an essence includes efficient causes, the usual kind of natural causes. Therefore, essence has a constitutive as well as a causal role. By being the ground of properties, essence is also important for modal metaphysics in that it determines that some properties belong to a thing by 5 See, e.g., Anjum and Mumford 2011, Greco and Groff 2013. 6 See, e.g., Vetter 2015. 7 In this paragraph, I am generally following Ayers 1991: 18-25, Bolton 1999, Anstey 2011, and Pasnau 2011: ch. 24 and 27. 8 See Pasnau 2011: 557ff. for discussion of the two roles of essence. (He speaks of “substantial form”, but this comes to the same because the two notions were usually equated in the 17th century and thereafter.) 3 necessity, others are consistent with it, and yet others are excluded from belonging to the thing. This account of essence was widely present in the 16th and 17th century.9 Locke opposes the Scholastic conception of essence and departs from it in a number of ways. First, he famously distinguishes between nominal and real essence.10 Nominal essence consists of ideas11, whereas real essence consists of the “primary qualities” of things, such as solidity and extension.12 Second, Locke rejects the notion of “substantial form” as “wholly unintelligible” (Locke, E 3.6.10)13, and, in contrast to the traditional understanding of essences, Locke’s real essence is contingent and alterable.14 Third, nominal essence is dependent on the powers of a thing (the “secondary qualities”), and powers are grounded in primary qualities.